Updated for USM #130. Involved a lot of breaking up the issue by page numbers to fit it chronologically with Ultimatum, UFF, and UXM. At least the continuity is holding up so far, even if the story itself isn't worth the paper its printed on. I checked and re-checked, but let me know if anything looks out of place to any of you. As it stands now, the Ultimatum timeline looks like this:
Ultimate Spider-Man #129, "Ultimatum, Part 1"
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 1-4)
Ultimatum #1, "Three Kings" (pg. 1-4)
Ultimate X-Men #98, "Ultimatum, Part 1" (pg. 1)
Ultimatum #1, "Three Kings" (pg. 5-7)
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 5)
Ultimate X-Men #98, "Ultimatum, Part 1" (pg. 2-3)
Ultimatum #1, "Three Kings" (pg. 8-10)
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 6-8)
Ultimatum #1, "Three Kings" (pg. 11)
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 9-11)
Ultimatum #1, "Three Kings" (pg. 12-24)
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 12-20)
Ultimate X-Men #98, "Ultimatum, Part 1" (pg. 4-22)
Ultimate X-Men #99, "Ultimatum, Part 2" (pg. 1-3)
Ultimatum #2, "Death Becomes Her" (pg. 1-4)
Ultimate Spider-Man #130, "Ultimatum, Part 2" (pg. 21-22)
Ultimatum #2, "Death Becomes Her" (pg. 5-11)
Ultimate Fantastic Four #58, "Ultimatum, Part 1" (pg. 3-7)
Ultimatum #2, "Death Becomes Her" (pg. 12-25)
Ultimate Fantastic Four #58, "Ultimatum, Part 1" (pg. 9-12, 14-15, 18-22)
Ultimate Fantastic Four #59, "Ultimatum, Part 2" (pg. 3-8, 10-12, 15-22)
Ultimate Fantastic Four #60, "Ultimatum, Part 3"**
Ultimate X-Men #99, "Ultimatum, Part 2" (pg. 4-22)
Ultimate X-Men #100, "Ultimatum, Part 3"**
Ultimate Spider-Man #131, "Ultimatum, Part 3"**
Ultimate Spider-Man #132, "Ultimatum, Part 4"**
Ultimate Spider-Man #133, "Ultimatum, Part 5"**
Ultimatum #3**
Ultimatum #4**
Ultimatum #5**